Production of hydrogen



P 6, 1932- c. F. R. HARRISON 1,875,923

I PRODUCTION OF HYDROGEN Filed April 11. 1950 msnmu: STEAM AIR IN Igv IN L2 Mag y:

Patented Sept. 6, 1932 UNITED STATES PATENT. OFFICE CHARLES FREDERICK REED HARRISON; OF NORTON-ON-TEES, ENGLAND, ASSIGNOR TO IMPERIAL CHEMICAL INDUSTRIES LIMITED, 01 LONDON, ENGLAND, A BRITISH COMPANY PRODUCTION OF HYDROGEN Application fled April 11, 1930, Serial No. 443,487fand in Great Britain April 19, 1929.

This invention relates to the production of hydrogen by the thermal decomposition of methane and similar hydrocarbons and also by the decomposition of steam with carbon.

5 It is known that hydrogen may be obtained by passing methane or a gas containing'meth ane such as coke oven gas through a bed of incandescent coke. It is also known that a mixture of hydrogen and water gas may be obtained by passing a mixture of methane and steam through a bed of incandescent coke, and that the temperature of the coke bed may be maintained by intercalary blowing periods with air.

According to the. present invention hydrogen is obtained by the separate and consecutive passage through an incandescent coke bed of a methane-containing gas and steamrespectively. The temperature of the coke bed is restored as required by blowing with air. The invention further includes processes'in which a refractory inert material is used for storage of heat as hereafter described. Powdered carbonaceous material for combustion.

When using a coke bed, at the commencement, the temperature of thecoke bed should be as high as possible, e. g. 1500. The supply of methane gas is then turned on and a gas consisting practically entirely of hydrogen is collected. When the temperature of the coke bed has fallen to such a degree that unchanged methane commences to appear in the exit gas, the methane supply is cut ofi and steam is substituted. The temperature at this point of the cycle may be about 1100. The production of watergas is then carried on until the temperature of the coke bed has 9 fallen to say 900, when the steam supply is cut off arid an air blast substituted. This carries the temperature again to a very high level and enables the cycle to start again with the introduction of methane gas.

' The hydrogen gas obtained in the run with may be used for the water gas reaction and/ or methane is collected separately from the water gas obtained in the run with steam.

The water gas may be catalysed with steam is well. adapted for use in the process of this invention.

The process of the invention is particularly important in conjunction with processes for the destructive hydrogenation of coal, etc. as in these processes large quantities of methane are produced and can be separated by solution in kerosene for example, whereupon the methane can be disposed of in the manner already described with the production of practically pure hydrogen which can be used in the" hydrogenation process. Asthe whole of the hydrogen requirements of a coal hydrogenation process can be met by this method, it is evident that the combi nation of the present process with destructive hydrogenation is of great economic importance.

The process can be carried on without the addition of coke, to the coke bed since the carbon resulting from the decomposition of methane is sufficient to supply the normal requirements but in some cases it may be necessary to add a further suppiy of-coke during operation. Y

The process may also be carried out using a mass of refractory material for example chequer-brickwork as a means for conveying heat to the methane. In this case thebrickwork should be heated up initially with a mixture of pulverized fuel and The reaction may then be self-sup orting, or alternative powdered .fuel ma supplied with the steam, and with t e air, 1n amounts depending on the amount of carbon deposited during the period of methane decomposition.

The gases coming to and from the reaction chamber should be led through regenerators or recuperators to recover their sensible heat.

A purge of steam may be intercalated between the air blast and the methane blast, to eliminate the risk of explosion.

The invention may be carried out in the apparatus shown in the accompanying dia gram.

Here 1 is a chamber filled with coke or refractory material 2. Methane is' introduced by pipe 3 and the hydrogen produced leaves by pipe 6. Steam is intro need by pipe 4 and the water gas produced leaves by pipe 7. Air is introduced by pipe 5 and the gases of combustion leave by pipe 8.

" cutting off said air, passing in methaneuntil the temperature falls to about 1100 C. cutting off said methane, passing in steam until the temperature falls to about 900 0. cutting off said steam, and then repeating the cycle.

3. The process of producing hydrogen which comprises the successive steps of passing methane through a highly heated refractory material to convert it into hydrogen and carbon, shutting off said methane, passing in steam to react w1th carbonaceous materlal in the same apparatus, shutting off said steam and raising the temperature of the apparatus by combustion.

4. The process of producing hydrogen which comprises the successive steps of heating up a refractory material by burnin powdered fuel and air, shutting off sai powdered fuel and air, passing methane into said refractory material to decompose it into carbon and hydrogen, shutting oflf said methane, and passing in steam to react with said carbon and produce water gas, shutting ofl said steam and repeating the cycle.

5. The process of producing hydrogen which comprises the successive steps of heating up a refractorymaterial by burning powdered fuel and air, shutting off said powdered fuel and air, passing methane into said refractory material to decompose it into carbon and hydrogen, shutting off said methane, injecting a mixture of steam and powdered fuel to produce water gas, shutting off said mixture and repeating the cycle.

ucing hydroggg methane, passing steam through'said coke, to form water gas, shutting off said steam and repeating the cycle.

In witness whereof, I have hereunto signed my name this 18th day ofMarch, 1930.

I) CHARLES FREDERICK REED HARRISON. 

